Capturing reflected light from a sampling surface

ABSTRACT

A mechanism is disclosed for capturing reflected rays from a surface. A first and second lens aligned along a same optical center axis are configured so that a beam of light collimated parallel to the lens center axis directed to a first side, is converged toward the lens center axis on a second side. A first light beam source between the first and second lenses directs a light beam toward the first lens parallel to the optical center axis. Second light beam source(s) on the second side of the first lens, direct a light beam toward a focal plane of the first lens at a desired angle. An image capturing component, at the second side of the second lens, has an image capture surface directed toward the second lens to capture images of the light reflected from a sample capture surface at the focal plane of the first lens.

BACKGROUND

Real-life objects can look different when viewed from different anglesand when illuminated from different directions and/or angles. Forexample, when facing a low lying sun, a landscape may have aparticularly different appearance than when viewing the same landscapeat high noon. Painters and photographers often explore the appearance oftrees, landscapes, people and urban areas under a variety of conditions,in order to accumulate knowledge about “how things look”.

A reason that things look differently under different conditions can berelated to how light is reflected from the surface of viewed objects.Light reflected in one direction may make an object appear differentthan when it is reflected in a different direction. Further, structuraland optical properties of the surface of viewed objects, such asshadow-casting, multiple scattering, mutual shadowing, transmission,reflection, absorption and emission by surface elements, can also affecthow an object appears. These characteristics of an object can besummarized by the reflectance on real-world objects, and the reflectanceof a surface can be determined by a Bidirectional ReflectanceDistribution Function (BRDF). Determining BRDFs, for example, can beuseful for creating realistic computer-generated (CG) images.

SUMMARY

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key factors oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter.

When one wishes to model a particular object, for example, as acomputer-generated (CG) image (e.g., a piece of architecture, tree,furniture, etc.), they may attempt to determine BidirectionalReflectance Distribution Functions (BRDFs) for that object. However,capturing BRDFs that have high resolution in both a spatial and angulardomain is difficult. The surface of an object can often comprise amyriad of variations in surface elements, angles, and materials thatabsorb or reflect light, each of which adds to how that object appearsin the real-world. Measuring BRDFs for various objects can generallytake hours of measurement and processing, and use of large, specializedand expensive hardware rigs. As a result, not many materials have beenmeasured for high resolutions BRDFs.

Systems are disclosed that provide for a relatively small, inexpensive,and easily manipulated apparatus that can capture images of lightreflected from a sampled surface. Further, the disclosed systems canprovide a variety of illumination positions and angles, therebyproviding a more complete and accurate sequence of reflectance imagesfrom a sample, for example, when moved across the sample's surface. Theimage information captured by the systems described herein may beutilized to determine BRDFs for the surface of an object, for example,thereby providing for more accurate CG imagery, in a more efficient andcost effective manner than is conventionally known.

In one embodiment of an apparatus for capturing a field of reflectedrays from a sample surface, at least a first and second lens aredisposed along a same optical center axis, where the respective lensesare configured so that a beam of light, passing through the lens andcollimated parallel to the lens center axis from a first side, isconverged toward the lens center axis on a second side. Further, atleast one first light beam source is between the first and secondlenses, directing a light beam toward the first lens parallel to theoptical center axis. Additionally, one or more second light beam sourcesare on the second side of the first lens, and they direct a light beamtoward a focal plane of the first lens at a desired angle from the focalplane. An image capturing component at the second side of the secondlens has an image capture surface directed toward the second lens, andit captures images of the light reflected from a sample capture surfaceat the focal plane of the first lens.

To the accomplishment of the foregoing and related ends, the followingdescription and annexed drawings set forth certain illustrative aspectsand implementations. These are indicative of but a few of the variousways in which one or more aspects may be employed. Other aspects,advantages, and novel features of the disclosure will become apparentfrom the following detailed description when considered in conjunctionwith the annexed drawings.

DESCRIPTION OF THE DRAWINGS

FIG. 1A is a component diagram illustrating an exemplary apparatus forcapturing a hemispherical field of reflected rays from a sample surface.

FIG. 1B is component diagram illustrating an exemplary system forcapturing sparse light direction measurements from reflected rays from asample surface.

FIG. 2 is an example embodiment of an apparatus in accordance with theone or more systems disclosed herein.

FIG. 3 is an example embodiment of an apparatus in accordance with theone or more systems disclosed herein.

FIGS. 4A-D are example embodiments illustrating arrangements of lightbeam sources in an apparatus in accordance with the one or more systemsdescribed herein.

FIG. 5 is an example embodiment illustrating arrangements of imagecapture devices in accordance with the one or more systems describedherein.

FIG. 6 is an example embodiment of a device in accordance with the oneor more systems disclosed herein.

FIGS. 7A-C are example embodiments illustrating a variety ofarrangements of components in an apparatus in accordance with the one ormore systems described herein.

FIGS. 8A-B are example embodiments illustrating concepts in accordancewith the one or more systems disclosed herein.

FIG. 9 illustrates an exemplary computing environment wherein one ormore of the provisions set forth herein may be implemented.

DETAILED DESCRIPTION

The claimed subject matter is now described with reference to thedrawings, wherein like reference numerals are used to refer to likeelements throughout. In the following description, for purposes ofexplanation, numerous specific details are set forth in order to providea thorough understanding of the claimed subject matter. It may beevident, however, that the claimed subject matter may be practicedwithout these specific details. In other instances, structures anddevices are shown in block diagram form in order to facilitatedescribing the claimed subject matter.

An apparatus may be devised that provides for capturing light reflectedfrom a surface that is subjected to sampling. That is, for example,light directed toward a surface intended to be sampled can reflect fromthe sample surface and be captured for further processing. Lightdirected toward a surface can exhibit a variation of reflectance, whichcan also vary with different materials. Rich details of a material'ssurface may also change based on a position of the observer and aposition of the light source. Surfaces of a variety of materials can besampled, and light reflected from the sampling surface can be captured,for example, to create a computer-generated image of a surface whichexhibits “real-world” visual characteristics of the sampled material.

FIG. 1 is a component diagram illustrating an exemplary apparatus 100that can be used to capture a hemispherical field of reflected rays froma sample surface. A first lens 104 and second lens 102 are disposed suchthat they are aligned along a same optical center axis 106. Further, thelenses 102, 104 are disposed in manner that when a beam of light 116,which is collimated parallel to the lens's center axis 106, passesthrough a first side of the lens 104A the beam 116 is converged towardthe lens's center axis 106, (e.g., at a front side of the lens).Additionally, the lenses 102, 104 are disposed in a manner where thefirst side 104A of the first lens 104 faces the first side 102A of thesecond lens 102.

A first light beam source 114 (or more than one) is disposed between thefirst lens 104 and the second lens 102. The first light beam source 114directs a light beam 116 toward the first lens 104 parallel to theoptical center axis 106. One or more second light beam sources 128 aredisposed at the second side 104B of the first lens 104, where theydirect a beam of light 130 toward a focal plane 124 (e.g., at a focalpoint) of the first lens 104 at a desired angle (e.g., chosen for adesired reflectance affect) from the focal plane 124.

One or more second light beam sources 128 are disposed on the secondside 104B of the first lens 104. These one or more second light beamsources 128 respectively direct a light beam toward the focal plane 124of the first lens 104 at a desired angle from the focal plane 124. Thatis, for example, a second light beam source can provide side lighting toa sample surface that is placed at the focal plane. The second lightbeam sources provide the side lighting at a desired angle, for example,to compliment the top lighting provided by the first light beamsource(s). In this way, in this example, a plurality of reflections fromthe sample surface can be created from a plurality of positions, and atangles that may provide for desired resulting reflected light capture.

An image capturing component 112 is disposed on the second side 102B ofthe second lens 102. The image capturing component 112 has an imagecapture surface that faces the second lens 102, and captures images thatare made up of light reflected 118, 120, 122 from a sample capturesurface 126 at the focal plane 124 of the first lens 104. In oneembodiment, the image capture surface of the image capturing component112 can be disposed at a distance from a focal plane 108 (e.g.,comprising a focal point) of the second lens 102, that provides adesired image focus for the reflected light 118, 120, 122.

In one embodiment, the first and second light beam sources 114, 128 aredirected toward an intended sample surface 126, at a desired point onthe surface. That is, for example, a plurality of second light beamsources 128 can be pointed toward the focal plane 124 of the first lens104, and the first light beam source 114 can be positioned such that itsbeam of light 116 is converged at the focal plane of the first lens. Inthis way, in this example, the first light beam source 114 provides atop light source, and the second light beam sources 128 provide sidelight sources from a variety of positions. Therefore, light is reflected118, 120, 122 from the sample surface 126 at a plurality of angles andpositions, and that reflected light 118, 120, 122 can be directed backto the second lens 102, which converges the reflected light toward it'sfocal plane 108. The reflected light can then be captured as an image(or series of images) by the image capture component 112.

In one aspect, real-world materials exhibit rich and detailedreflectance variation, for example, due to textures, surface shapes,types of materials, and other structural and optical properties of thesurface. These reflectances can be acquired to produce realisticcomputer-generated (CG) imagery of the materials. Objects lookdifferently when viewed from different angles/locations and when lightsources illuminate the objects from different angles/locations.Bidirectional reflectance distribution functions (BRDFs) givereflectance of a target surface as a function of illumination geometryand viewing geometry. That is, for example, a BRDF can help identifywhat an object's surface may look like based on the angle/location ofillumination, and the angle/location of the point of view. In thisaspect, light reflected from a surface at variety of locations andangles can be captured, and BRDFs may be determined for that material.In this way, in this example, the surface of an object may be morerealistically modeled for CG imagery.

In one embodiment, as illustrated in the exemplary embodiment 200 ofFIG. 2, an aperture 210 is defined between the image capturing component112 and the second lens 102, at the second side of the second lens. Thecenter of the aperture 210 is aligned along the optical center axis 106,and a plane formed by the aperture 210 is aligned with the focal plane108 of the second lens 102. In one embodiment, an aperture (e.g., 210)can provide for a desired cone angle for the reflected light (e.g., 118,120, 122) at the focal plane (e.g., 108), thereby providing a desiredimage quality (e.g., focus, depth of field, etc.) at the image capturesurface of the image capture device (e.g., 112).

An aperture can determine a cone angle of a plurality of reflected lightrays that come to focus on an image plane, such as at the image capturesurface. That is, for example, a small (e.g., narrow) aperture mayprovide for highly collimated light rays that result in a sharper imageat the image plane on the image capture surface. Whereas as a largeraperture, which provides for a plurality of uncollimated rays, mayresult in sharpness for merely those rays having a focal length thatmatches the image plane on the image capture surface. In this way, forexample, a size of the aperture may determine sharpness and other imagequalities for the images of reflected light at the image capturesurface.

In one embodiment, a device configured to detect reflected light, suchas the apparatus of FIG. 1, for example, can comprise a casing, asillustrated by the exemplary embodiment 300 of FIG. 3. In thisembodiment, the casing 332 can be configured to mitigate (e.g., preventmost if not all) light infiltration from outside the casing to insidethe casing. That is, for example, the casing is designed to merely allowlight from the first and second light beam sources to be directed towardthe sample surface, and be reflected back to the image capture device,preventing extraneous light from affecting the sampling. In this way, inthis example, light sources, angles and locations can be controlled forBRDF determination.

As illustrated in FIG. 3, the casing 332 can also be configured toprovide for mounting the lenses 102, 104 and aperture 210 inside thecasing in alignment along the optical center axis (e.g., 106 of FIG. 1).For example, the casing 332 may be cylindrical and have an innerdiameter that is devised to merely fit an outer diameter of acylindrical lens. In this way, for example, the lenses could be fastenedin place at an appropriate location, such as using a type of adhesive,or a mechanical fixture or fastener, inside the casing.

Further, as an example, the aperture 210 may be formed by mounting anaperture ring inside the casing. In one embodiment, the aperture ringmay be comprised of a same material, and formed together with thecasing. In another embodiment, the aperture ring may be inserted intothe casing and fastened therein at an appropriate location, such ascoplanar with the focal plane of the second lens. It will be appreciatedthat the aperture is not limited to any particular size, and may besized to fit a desired result for a particular application or sampling.

In one embodiment, as illustrated in the exemplary embodiment 300 ofFIG. 3, the casing can comprise a sample capture opening 334 that isdisposed at the second side of the first lens 104. The sample captureopening 334 can allow light from the first and second light sources 338,336 to reach a sample capture surface that is placed adjacent to thesample capture opening 334. As an example, the example embodiment of anapparatus 300 can be held against a surface that is intended forsampling, with the sample capture opening 334 held adjacent to thesampling surface, which is coplanar with the focal plane of the firstlens 104. In this way, in this example, light from the first lightsource 338 will focus on the sample surface, and light from the secondlight source(s) will illuminate the sample surface.

In the above example, light reflected from the sample surface isdirected toward the first lens 104, and back toward the image capturesurface 112 of the image capture component. In one embodiment, thecasing 332 can comprise a mechanism for mounting at least the imagecapture surface 112 of the image capture component inside the casing.That is, for example, the casing 332 can be devised to provide a way tomount the image capture surface 112 at an appropriate distance 340 fromthe aperture 210, such that the image capture surface 112 is coplanarwith a desired image plane for light reflected from the sample surface.In this way, in this example, at least the image capture surface 112 ismounted inside the casing 332 so that merely reflected light from thesample surface reaches its surface, and not light from outside thecasing 332.

It will be appreciated that the systems described herein are not limitedto any particular embodiment for mounting the image capture component.For example, merely the image capture surface, such as a complementarymetal-oxide-semiconductor (CMOS) sensor, of the image capture component,such as a digital camera, can be located inside the casing in order tocapture the reflected light. However, in another example, an entirecamera, or portions thereof, may be disposed inside the casing such thatthe reflected light reaches the sensor of the camera at the desiredimage plane.

FIG. 6 illustrates one exemplary embodiment 600, where the image capturedevice 602 is comprised outside of the casing 332, and merely the imagecapture surface 112 is disposed inside the casing 332 at a distance 340from the aperture 210 that provides for capturing the reflected light ata desired image plane, for example. FIG. 7A illustrates another exampleembodiment 700, where the image capture device 602 is disposed entirelyinside the casing, such that the reflected light is captured at adesired image plane. In another embodiment, the image capture surfacemay comprise a lens that focuses the reflected light to an image lightsensor, such as a CMOS sensor, in a camera, for example.

In one embodiment, the casing 332 can comprise a mechanism for mountingthe light beam sources. As illustrated in the exemplary embodiment 300of FIG. 3, a light beam source may be comprised of a light source 338,336 and a light tube 339, 337, which can direct the light from the lightsource as a beam to a desired location. For example, the light source338, 336 may comprise a light emitting diode (LED), which typicallyemits light in a plurality of directions. The light source can bedisposed in a light tube 339, 337 such that merely a light beam isemitted at a desired direction. The light beam source (e.g., comprisedof the light source 338, 336 and the light tube 339, 337) can be mountedby a mechanism comprised by the casing.

In one embodiment, the mechanism for mounting the first light beamsource 338, 339 may be comprised of an optically clear casing insert 342that anchors the first light beam source 338, 339 at a desired positionbetween the first and second lenses 104, 102. As an example, an acrylicdisk (e.g., 342) may be inserted inside the casing, in which can bemounted the first light beam source at a desired position. In thisexample, the acrylic disk (or some other optically clear polymer, glass,or material that does not alter an angle of light passing through it ata perpendicular direction) may comprise an opening in which the lighttube (e.g., 339) of the light beam source can be mounted.

In one embodiment, the first light beam source is disposed at a distancefrom the optical center axis that provides for light from the firstlight beam source to reach the lens axis at a desired angle of bias fromthe optical center axis. That is, for example, with reference to FIG. 1,varying the distance between the first light beam source 114 from theoptical center axis 106 can vary the angle at which the light beam 116from the first light beam source intersects the optical center axis 106at the focal plane 124. As illustrated in FIG. 1, a light beam directedtoward the first lens 104 from position 122 has a larger angle of biasfrom the optical center axis 106 than the light beam directed from theposition 118. The first light beam source may be mounted at such adistance that provides for a desired result, such as for a desired typeof sampling. Further, a plurality of first light beam sources may bemounted at a same or varied distances from the optical center, forexample, in order to provide top lighting for the sample surface from avariety of angles.

In one embodiment, the mechanism for mounting the one or more secondlight beam sources can provide for mounting the second light beam sourceentirely inside the casing, such as illustrated in the exampleembodiments 400 of FIG. 4A and 440 of FIG. 4B. That is, for example,five second light beam sources 128A-E can be arranged relativelyequidistant from each other around the sample capture opening 334,mounted in such a way as to provide for the second light beam sources128 to direct their light beams toward the sample capture opening 334(e.g., to provide a plurality of lighting perspectives).

In another embodiment, the mechanism for mounting the one or more secondlight beam sources 128 can provide for mounting the second light beamsource 128 so in a way that merely provides for the light beam to bedirected toward the sample capture surface placed adjacent to the samplecapture opening 334. That is, for example, the mounting mechanism mayprovide for mounting the second light beam source (e.g., 128A-E)completely or partially outside the casing 332, in a way that allows thelight to still reach the sample capture opening 334. One example of thisembodiment is illustrated in FIG. 4C, where the casing 332 comprisesopenings 462 that provide for mounting the five second light beamsources 128A-E, so that the light beams are directed toward the samplecapture opening 334.

It will be appreciated that the number of first and second light beamsources are not limited to the embodiments described herein. As anexample, as illustrated by the exemplary embodiment 480 of FIG. 4D, aplurality of second light beam sources 128, 130 may be disposed aroundthe sample capture opening 334. In one embodiment, a size of the samplecapture opening, which may be dictated by a type and size of a sampledsurface, may necessitate additional second light beam sources, and/orfirst light beam sources 114.

As illustrated in the exemplary embodiment 800 of FIG. 8A, five secondlight beam sources may provide five illuminated areas 804A-E on a samplecapture surface 850 in the sample capture opening 324, while the firstlight beam source provides a single illuminated area 802 on the samplecapture surface 850 in the sample capture opening 324. In this way, forexample, a significant portion of the sample surface 850 can beilluminated during sampling. In another embodiment, as illustrated in820 of FIG. 8B, eight second light beam sources can provide for eightilluminated areas 804A-H on a sample capture surface 850 in the samplecapture opening 324. Further, in this embodiment, three first light beamsources can provide three illuminated areas 802A-C on a sample capturesurface 850 in the sample capture opening 324.

In one embodiment, the respective lenses may comprise plano-convexcondenser lenses, where the first side of each lens is a non-focal-pointside and the second side is a focal-point side. An example ofplano-convex lenses is illustrated in the exemplary embodiment 700 ofFIG. 7. The lenses 102 and 104 respectively comprise a flat side (plano)and a side that curves outward (convex). In this example, the focalpoint side is typically the flat side of the lens, where light beams arefocused toward the lens's central axis, and the non-focal point side istypically the convex side, where light beams are collimated parallel tothe lens's central axis.

It will be appreciated that the lenses and lens arrangements are notlimited to those embodiments described above. As an example, asillustrated by the exemplary embodiment 700 of FIG. 7A, 740 of FIG. 7B,and 780 of FIG. 7C, the lens may be different shapes and can be arrangedin different configurations. As an example, in FIG. 7A, the respectivelenses 102, 104 are plano-convex and are arranged such that the convexsides face each other. In this example 700, the first light beam source714 is disposed on the plano side of lens 102, angled such that whenthen light beam from this light passes through lens 102, it iscollimated to the center axis before reaching lens 104. At lens 104, thelight beam is converged toward the focal plane of lens 104, for example,at the sample surface.

In the example 740, the lenses 102, 104 are bi-convex. This arrangementof lenses can also provide for light beams to be focuses toward thecenter axis at either side of the lens arrangement. In this way, lightfrom the first light beam source 714 is converged toward the axis oflens 104, for example, at a sample surface. The resulting reflectedlight is collimated by lens 104 parallel to the center axis, and at lens102, it is converged towards a focal plane, for example, and theresulting image can be captured at the image plane by the image capturecomponent 602.

Further, the apparatus is not limited to merely two lenses. For example,as illustrated in FIG. 7C, respective bi-convex lenses 102 and 104 aredisposed adjacent to two plano-concave lenses 752, 754. As describedabove, light from the first light beam source 714 is converged towardthe axis of the combined lenses 104 and 754, for example, at the samplesurface. The resulting reflected light is collimated by the combinedlenses 104 and 754 parallel to the center axis, and at the combinedlenses 102 and 752, the reflected light is converged towards the focalplane.

In one embodiment, the image capture component may have a computingdevice connector that allows for images captured by the image capturedevice to be provided to a computing device. FIG. 5 illustrates anexemplary embodiment 500 of how the apparatus may be connected to acomputing device. The image capture component 546, having its imagecapture surface disposed inside the casing 332, is connected 542 to acomputing device 544. The connection between the image capture component546 and the computing device is not limited to any particularembodiment. For example, common connections utilized may comprise anIEEE 1394 interface (e.g., firewire), a USB connection, or a wirelessconnection (e.g., radio frequency, such as wifi or Bluetooth). In thisway, for example, the captured images can be processed by the computingdevices, such as to compute BRFDs.

As an alternate embodiment, FIG. 1B illustrates an example system 150for capturing sparse light direction measurements from reflected raysfrom a sample surface. A compound lens 101 comprising at least twolenses 103 and 105, where the compound lens has a focal plane 125, 109at both a first 105B and second 103B end. A first light source 115directs light 117 toward the focal plane 125 at the first end 105B,where a light beam 117 from the first light source 115 has an angle ofbias from an optical center axis 107 of the compound lens 101 of greaterthan or equal to zero degrees and less than or equal to forty-fivedegrees.

In this embodiment 150, one or more second light sources 129 directlight 131 toward the focal plane 125 at the first end 105B, where alight beam 131 from the second light source 129 has an angle of biasfrom the focal plane 125 of less than or equal to forty-five degrees andgreater than or equal to zero degrees. An image capture device 113 isdisposed at the second end 103B to capture light reflected from thefocal plane 125 of the first end 105B at an image plane of the secondend 103B.

In one embodiment, the image plane of the second end, such as disposedcoplanar to an image capture surface of the image capture device 113,and the second end 103B of the compound lens 101 define an aperture(e.g., as illustrated by 210 of FIG. 2) between them, where the apertureis coplanar with the focal plane 109 of the second end 103B, with itscenter aligned along the optical center axis 107. As described above,this aperture can provide a desired cone angle for the reflected light,such as from a sample surface disposed coplanar to the focal plane 125at the first end 105B.

In one embodiment, the exemplary system described above can be disposedin a casing that mitigates light infiltration from outside to inside thecasing, such as illustrated by 332 of FIG. 3. In this embodiment, withreference to FIG. 1B and FIG. 3, the casing can comprise a samplingwindow (e.g., 334) that is disposed at the first end 105B adjacent tothe focal plane 125 of the first end 105B. The sampling window canprovide for light from the first 115 and second 129 light sources toreach a sample surface that may be placed adjacent to the samplingwindow, such as at the focal plane 125.

Further, in this embodiment, the casing can comprise a mechanism formounting an image capture surface (e.g., 112 of FIG. 3) of the imagecapture device 113 at the image plane of the second end 103B. In thisway, as described above, at least the image capture surface is disposedinside the casing, thereby allowing merely light reflected from thesample surface to be captures by the image capture device, for example,and not extraneous light.

In one embodiment, with reference to FIG. 1B and FIG. 3, the exemplarysystem can comprise a first light source mounting mechanism (e.g., 342)that provides for mounting the first light source 115 so that light fromthe first light source 115 remains inside the casing (e.g., 332) untillight from the first light source 115 reaches the sampling window (e.g.,334). That is, the mounting mechanism allows the first light source todirect light toward the first end 105B of the compound lens 101, whereit is converged toward the focal plane 125 of the first end 105B, forexample, at which may be placed a sample surface.

Further, in this embodiment, the exemplary system can comprise a secondlight source mounting mechanism that provides for mounting the secondlight source 129 so that light from the second light source 129 remainsinside the casing (e.g., 332) until light from the second light source129 reaches the sampling window (e.g., 334). That is, the mountingmechanism provides for the one or more second light sources, forexample, to be mounted around the sampling window, with their lightbeams directed toward the focal plane 125 of the second end 105B.

In one embodiment, the first light source can be disposed between thefirst 105 and second 103 lens inside the compound lens 101. In thisembodiment, light 117 from the first light source 115 is directed towardthe sampling window (e.g., 334), and the first and second lens aredisposed in a manner inside the compound lens 101 that merelyaccommodates the first light source 115. In this embodiment, the firstlight source 115 is placed between the lenses of the compound lens, withits beam aiming toward the first end 105B, for example, to provide toplight illumination to a sample surface at the focal plane 125. In thisembodiment, for example, an optically clear disk (e.g., 342) may beemployed to mount the first light source 115 between the lenses in thecompound lens 101.

In one embodiment, with reference to FIGS. 1B and 5, the image capturedevice 113 has a mechanism (e.g., 542) that provides for images capturedby the image capture device to be provided to a computing device (e.g.,544). In this embodiment, the computing device can be configured tocompute microfacet bidirectional reflectance distribution functions(BRDFs). That is, for example, a plurality of images of reflected lightmay be collected by the image capture device 113 as the casingcomprising the exemplary system is moved over a sample surface. In thisway, in this example, the plurality of images may be used by thecomputing device to calculate BRDFs for the sample surface (e.g., tocreate CG images of the surface).

In one embodiment, the exemplary system, such as 150 of FIG. 1B, maycomprise a mechanism for adjusting particular elements of the system. Amechanism may be provided that adjusts the aperture (e.g., 210 of FIG.2), such as to sharpen the image at the image plane on the image capturesurface. Further, a mechanism may be provided that adjusts a distance ofthe aperture from the image capture surface, such as to provide foradditional focus and image enhancements. Additionally, a mechanism maybe provided that adjusts a distance between the first and second lens,such as to adjust the focal plane at either or both of the first andsecond ends of the compound lens.

In another embodiment, other adjustment mechanisms may be provided. Amechanism may be provided that adjusts a color of the respective lightssources, for example, in order to correct for sample surface conditions.A mechanism may be provided that adjusts a brightness of respectivelight sources, such as to enhance or adjust desired sampling conditions.

Although the subject matter has been described in language specific tostructural features and/or methodological acts, it is to be understoodthat the subject matter defined in the appended claims is notnecessarily limited to the specific features or acts described above.Rather, the specific features and acts described above are disclosed asexample forms of implementing the claims.

As used in this application, the terms “component,” “module,” “system”,“interface”, and the like are generally intended to refer to acomputer-related entity, either hardware, a combination of hardware andsoftware, software, or software in execution. For example, a componentmay be, but is not limited to being, a process running on a processor, aprocessor, an object, an executable, a thread of execution, a program,and/or a computer. By way of illustration, both an application runningon a controller and the controller can be a component. One or morecomponents may reside within a process and/or thread of execution and acomponent may be localized on one computer and/or distributed betweentwo or more computers.

Furthermore, the claimed subject matter may be implemented as a method,apparatus, or article of manufacture using standard programming and/orengineering techniques to produce software, firmware, hardware, or anycombination thereof to control a computer to implement the disclosedsubject matter. The term “article of manufacture” as used herein isintended to encompass a computer program accessible from anycomputer-readable device, carrier, or media. Of course, those skilled inthe art will recognize many modifications may be made to thisconfiguration without departing from the scope or spirit of the claimedsubject matter.

FIG. 9 and the following discussion provide a brief, general descriptionof a suitable computing environment to implement embodiments of one ormore of the provisions set forth herein. The operating environment ofFIG. 9 is only one example of a suitable operating environment and isnot intended to suggest any limitation as to the scope of use orfunctionality of the operating environment. Example computing devicesinclude, but are not limited to, personal computers, server computers,hand-held or laptop devices, mobile devices (such as mobile phones,Personal Digital Assistants (PDAs), media players, and the like),multiprocessor systems, consumer electronics, mini computers, mainframecomputers, distributed computing environments that include any of theabove systems or devices, and the like.

Although not required, embodiments are described in the general contextof “computer readable instructions” being executed by one or morecomputing devices. Computer readable instructions may be distributed viacomputer readable media (discussed below). Computer readableinstructions may be implemented as program modules, such as functions,objects, Application Programming Interfaces (APIs), data structures, andthe like, that perform particular tasks or implement particular abstractdata types. Typically, the functionality of the computer readableinstructions may be combined or distributed as desired in variousenvironments.

FIG. 9 illustrates an example of a system 910 comprising a computingdevice 912 configured to implement one or more embodiments providedherein. In one configuration, computing device 912 includes at least oneprocessing unit 916 and memory 918. Depending on the exact configurationand type of computing device, memory 918 may be volatile (such as RAM,for example), non-volatile (such as ROM, flash memory, etc., forexample) or some combination of the two. This configuration isillustrated in FIG. 9 by dashed line 914.

In other embodiments, device 912 may include additional features and/orfunctionality. For example, device 912 may also include additionalstorage (e.g., removable and/or non-removable) including, but notlimited to, magnetic storage, optical storage, and the like. Suchadditional storage is illustrated in FIG. 9 by storage 920. In oneembodiment, computer readable instructions to implement one or moreembodiments provided herein may be in storage 920. Storage 920 may alsostore other computer readable instructions to implement an operatingsystem, an application program, and the like. Computer readableinstructions may be loaded in memory 918 for execution by processingunit 916, for example.

The term “computer readable media” as used herein includes computerstorage media. Computer storage media includes volatile and nonvolatile,removable and non-removable media implemented in any method ortechnology for storage of information such as computer readableinstructions or other data. Memory 918 and storage 920 are examples ofcomputer storage media. Computer storage media includes, but is notlimited to, RAM, ROM, EEPROM, flash memory or other memory technology,CD-ROM, Digital Versatile Disks (DVDs) or other optical storage,magnetic cassettes, magnetic tape, magnetic disk storage or othermagnetic storage devices, or any other medium which can be used to storethe desired information and which can be accessed by device 912. Anysuch computer storage media may be part of device 912.

Device 912 may also include communication connection(s) 926 that allowsdevice 912 to communicate with other devices. Communicationconnection(s) 926 may include, but is not limited to, a modem, a NetworkInterface Card (NIC), an integrated network interface, a radio frequencytransmitter/receiver, an infrared port, a USB connection, or otherinterfaces for connecting computing device 912 to other computingdevices. Communication connection(s) 926 may include a wired connectionor a wireless connection. Communication connection(s) 926 may transmitand/or receive communication media.

The term “computer readable media” may include communication media.Communication media typically embodies computer readable instructions orother data in a “modulated data signal” such as a carrier wave or othertransport mechanism and includes any information delivery media. Theterm “modulated data signal” may include a signal that has one or moreof its characteristics set or changed in such a manner as to encodeinformation in the signal.

Device 912 may include input device(s) 924 such as keyboard, mouse, pen,voice input device, touch input device, infrared cameras, video inputdevices, and/or any other input device. Output device(s) 922 such as oneor more displays, speakers, printers, and/or any other output device mayalso be included in device 912. Input device(s) 924 and output device(s)922 may be connected to device 912 via a wired connection, wirelessconnection, or any combination thereof. In one embodiment, an inputdevice or an output device from another computing device may be used asinput device(s) 924 or output device(s) 922 for computing device 912.

Components of computing device 912 may be connected by variousinterconnects, such as a bus. Such interconnects may include aPeripheral Component Interconnect (PCI), such as PCI Express, aUniversal Serial Bus (USB), firewire (IEEE 1394), an optical busstructure, and the like. In another embodiment, components of computingdevice 912 may be interconnected by a network. For example, memory 918may be comprised of multiple physical memory units located in differentphysical locations interconnected by a network.

Those skilled in the art will realize that storage devices utilized tostore computer readable instructions may be distributed across anetwork. For example, a computing device 930 accessible via network 928may store computer readable instructions to implement one or moreembodiments provided herein. Computing device 912 may access computingdevice 930 and download a part or all of the computer readableinstructions for execution. Alternatively, computing device 912 maydownload pieces of the computer readable instructions, as needed, orsome instructions may be executed at computing device 912 and some atcomputing device 930.

Various operations of embodiments are provided herein. In oneembodiment, one or more of the operations described may constitutecomputer readable instructions stored on one or more computer readablemedia, which if executed by a computing device, will cause the computingdevice to perform the operations described. The order in which some orall of the operations are described should not be construed as to implythat these operations are necessarily order dependent. Alternativeordering will be appreciated by one skilled in the art having thebenefit of this description. Further, it will be understood that not alloperations are necessarily present in each embodiment provided herein.

Moreover, the word “exemplary” is used herein to mean serving as anexample, instance, or illustration. Any aspect or design describedherein as “exemplary” is not necessarily to be construed as advantageousover other aspects or designs. Rather, use of the word exemplary isintended to present concepts in a concrete fashion. As used in thisapplication, the term “or” is intended to mean an inclusive “or” ratherthan an exclusive “or”. That is, unless specified otherwise, or clearfrom context, “X employs A or B” is intended to mean any of the naturalinclusive permutations. That is, if X employs A; X employs B; or Xemploys both A and B, then “X employs A or B” is satisfied under any ofthe foregoing instances. In addition, the articles “a” and “an” as usedin this application and the appended claims may generally be construedto mean “one or more” unless specified otherwise or clear from contextto be directed to a singular form.

Also, although the disclosure has been shown and described with respectto one or more implementations, equivalent alterations and modificationswill occur to others skilled in the art based upon a reading andunderstanding of this specification and the annexed drawings. Thedisclosure includes all such modifications and alterations and islimited only by the scope of the following claims. In particular regardto the various functions performed by the above described components(e.g., elements, resources, etc.), the terms used to describe suchcomponents are intended to correspond, unless otherwise indicated, toany component which performs the specified function of the describedcomponent (e.g., that is functionally equivalent), even though notstructurally equivalent to the disclosed structure which performs thefunction in the herein illustrated exemplary implementations of thedisclosure. In addition, while a particular feature of the disclosuremay have been disclosed with respect to only one of severalimplementations, such feature may be combined with one or more otherfeatures of the other implementations as may be desired and advantageousfor any given or particular application. Furthermore, to the extent thatthe terms “includes”, “having”, “has”, “with”, or variants thereof areused in either the detailed description or the claims, such terms areintended to be inclusive in a manner similar to the term “comprising.”

1. An apparatus for capturing a hemispherical field of reflected raysfrom a sample surface, comprising: at least a first and second lens,respective lenses configured such that a beam of light, passing througha lens and collimated parallel to a lens center axis from a first side,is converged toward the lens center axis on a second side, respectivelenses aligned along an optical center axis, where a first side of thefirst lens faces a first side of the second lens; a first light beamsource disposed between the first and second lenses, configured todirect a first light beam toward the first lens parallel to the opticalcenter axis; one or more second light beam sources disposed on a secondside of the first lens, respectively configured to direct a second lightbeam toward a focal plane of the first lens at a desired angle from thefocal plane; and an image capturing component disposed on a second sideof the second lens, having an image capture surface directed toward thesecond lens, and configured to capture images comprised of lightreflected from a sample capture surface at the focal plane of the firstlens.
 2. The apparatus of claim 1, the image capturing component and thesecond lens defining an aperture therebetween disposed at the secondside of the second lens and having a center aligned along the opticalcenter axis, and a plane formed by the aperture aligned with a focalplane of the second lens.
 3. The apparatus of claim 1, comprising acasing configured to: mitigate light infiltration from outside thecasing to inside the casing; and provide for mounting the first andsecond lenses and an aperture inside the casing in alignment along theoptical center axis.
 4. The apparatus of claim 3, the casing comprisinga sample capture opening disposed at the second side of the first lens,and configured to allow light from the first and second light beamsources reach the sample capture surface placed adjacent to the samplecapture opening.
 5. The apparatus of claim 3, the casing comprising amechanism for mounting at least the image capture surface of the imagecapturing component inside the casing.
 6. The apparatus of claim 3, thecasing comprising a mechanism for mounting the first light beam sourceand at least some of the one or more second light beam sources.
 7. Theapparatus of claim 6, the mechanism for mounting comprising an opticallyclear casing insert configured to anchor the first light beam source ata desired position between the first and second lenses.
 8. The apparatusof claim 6, the mechanism for mounting configured to provide for:mounting at least some of the one or more second light beam sourcesentirely inside the casing; or mounting at least some of the one or moresecond light beam sources so that the second light beam is directedtoward the sample capture surface placed adjacent to the sample captureopening.
 9. The apparatus of claim 1, the first and second lensescomprising plano-convex condenser lenses.
 10. The apparatus of claim 1,the first light beam source disposed at a distance from the opticalcenter axis that provides for light from the first light beam source toreach the lens center axis at a desired angle of bias from the opticalcenter axis.
 11. The apparatus of claim 1, the image capture componentcomprising a computing device connector configured to communicate imagescaptured by the image capturing component to a computing device.